#include "Core.h"



__BEGIN_NAMESPACE

// first, some types:
typedef unsigned long uint4;  // assumes integer is 4 words long
typedef unsigned short uint2; // assumes short integer is 2 words long
#define uint1 unsigned char   // assumes char is 1 word long

// ROTATE_LEFT rotates x left n bits.
inline unsigned long rotate_left  (uint4 x, uint4 n){
	return (x << n) | (x >> (32-n))  ;
}

// F, G, H and I are basic MD5 functions.

inline unsigned long F            (uint4 x, uint4 y, uint4 z){
	return (x & y) | (~x & z);
}

inline unsigned long G            (uint4 x, uint4 y, uint4 z){
	return (x & z) | (y & ~z);
}

inline unsigned long H            (uint4 x, uint4 y, uint4 z){
	return x ^ y ^ z;
}

inline unsigned long I            (uint4 x, uint4 y, uint4 z){
	return y ^ (x | ~z);
}

// FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
// Rotation is separate from addition to prevent recomputation.


inline void FF(uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, 
			   uint4  s, uint4 ac){
				   a += F(b, c, d) + x + ac;
				   a = rotate_left (a, s) +b;
}

inline void GG(uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, 
			   uint4 s, uint4 ac){
				   a += G(b, c, d) + x + ac;
				   a = rotate_left (a, s) +b;
}

inline void HH(uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, 
			   uint4 s, uint4 ac){
				   a += H(b, c, d) + x + ac;
				   a = rotate_left (a, s) +b;
}

inline void II(uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, 
			   uint4 s, uint4 ac){
				   a += I(b, c, d) + x + ac;
				   a = rotate_left (a, s) +b;
}

// Encodes input (UINT4) into output (unsigned char). Assumes len is
// a multiple of 4.
inline void encode (uint1 *output, uint4 *input, uint4 len) {

	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j]   = (uint1)  (input[i] & 0xff);
		output[j+1] = (uint1) ((input[i] >> 8) & 0xff);
		output[j+2] = (uint1) ((input[i] >> 16) & 0xff);
		output[j+3] = (uint1) ((input[i] >> 24) & 0xff);
	}
}




// Decodes input (unsigned char) into output (UINT4). Assumes len is
// a multiple of 4.
inline void decode (uint4 *output, const uint1 *input, uint4 len){

	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((uint4)input[j]) | (((uint4)input[j+1]) << 8) |
		(((uint4)input[j+2]) << 16) | (((uint4)input[j+3]) << 24);
}

// Constants for MD5Transform routine.
// Although we could use C++ style constants, defines are actually better,
// since they let us easily evade scope clashes.

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

// MD5 basic transformation. Transforms state based on block.
void MD5Hash::Transform (const unsigned char* block){

	uint4 a = m_State[0], b = m_State[1], c = m_State[2], d = m_State[3], x[16];

	decode (x, block, 64);

	/* Round 1 */
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	/* Round 2 */
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	/* Round 3 */
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	/* Round 4 */
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	m_State[0] += a;
	m_State[1] += b;
	m_State[2] += c;
	m_State[3] += d;

	// Zeroize sensitive information.
	memset ( (uint1 *) x, 0, sizeof(x));

}


void MD5Hash::Init()
{
	m_State[0] = 0x67452301;
	m_State[1] = 0xefcdab89;
	m_State[2] = 0x98badcfe;
	m_State[3] = 0x10325476;

	m_Count[0] = 0;
	m_Count[1] = 0;
}

void MD5Hash::Finalize()
{
	unsigned char bits[8];
	unsigned int index, padLen;
	static uint1 PADDING[64]={
		0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	};

	// Save number of bits
	encode (bits, m_Count, 8);

	// Pad out to 56 mod 64.
	index = (uint4) ((m_Count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	Update (PADDING, padLen);

	// Append length (before padding)
	Update (bits, 8);

	// Store state in digest
	//encode (digest, state, 16);

	// Zeroize sensitive information
	//memset (buffer, 0, sizeof(*buffer));
}

void MD5Hash::Update( const unsigned char* data, size_t nbytes )
{
	uint4 input_index, buffer_index;
	uint4 buffer_space;                // how much space is left in buffer

	// Compute number of bytes mod 64
	buffer_index = (unsigned int)((m_Count[0] >> 3) & 0x3F);

	// Update number of bits
	if (  (m_Count[0] += ((uint4) nbytes << 3))<((uint4) nbytes << 3) )
		m_Count[1]++;

	m_Count[1] += ((uint4)nbytes >> 29);


	buffer_space = 64 - buffer_index;  // how much space is left in buffer

	// Transform as many times as possible.
	if (nbytes >= buffer_space) { // ie. we have enough to fill the buffer
		// fill the rest of the buffer and transform
		memcpy (m_Buf + buffer_index, data, buffer_space);
		Transform (m_Buf);

		// now, transform each 64-byte piece of the input, bypassing the buffer
		for (input_index = buffer_space; input_index + 63 < nbytes; 
			input_index += 64)
			Transform (data+input_index);

		buffer_index = 0;  // so we can buffer remaining
	}
	else
		input_index=0;     // so we can buffer the whole input


	// and here we do the buffering:
	memcpy(m_Buf+buffer_index, data+input_index, nbytes-input_index);
}


__END_NAMESPACE

